Pyrobombus (also known as Fiery-tailed bees) is a subgenus of bumblebees, with its centres of diversity in Central Asia and north-western North America. Nearly a fifth of all Bombus species fall within Pyrobombus and its member species vary considerably in size, appearance and behaviour. it covers 43 species of bees and is the largest subgenus of bumblebees, covering almost 50% of the North American fauna. They are seen to be declined by 6%, which may be an undervalued statistic, although not as high as other groups of bees. Pyrobombus bees also face issues such as climate change, loss of habitat, urbanization, and industrial agriculture. This subgenus of bees can pollinate that helps plants fertilise and grow fruit that is essential to the biodiversity and life of the environment. Commonly, Pyrobombus bees are used for beekeeping as they are pollinators. They can be for wax, honey, venom, combs, and such which may be collected for commercial use. This subgenus may vary in their characteristics such as body size, wingspan, and tongue length for individual species, but like all bees, they possess wings, a head, thorax, and abdomen. Morphology The Pyrobombus are fairly small bees. They are the largest subgenus group of the Bombus and the most diverse in its morphology. Along with its diversity, there are few similarities between the species. The Pyrobombus varies in tongue length, head shape, mouth-parts, wingspan and such. The coat color of the Pyrobombus is physically similar to other bees in different subgenera under the Bombus, with black, yellow, and orange pattern arrangements and with some species, the coat can have white patches and or stripes. Like all bees, species of the Pyrobombus have translucent wings that can have different colour tinges of clear, black, brown and amber. Phylogeny Reasons for investigating the origins of Pyrobombus can be due to questionable physical resemblance between the species and enzymes. Some studies of Pyrobombus phylogeny concludes this subgenus may not be monophyletic and is instead polyphyletic, where it shares multiple evolutionary ancestors; however, it is argued results that lead for the nature of Pyrobombus to be polyphyletic may be due to a smaller taxon representation. In the study by Hines, Cameron and Williams, they have gathered a larger taxon representation to investigate the phylogeny of Pyrobombus, and conclude that the phylogeny of the subgenus Pyrobombus to be monophyletic. They were able to analyze 36 of the 43 recognized